Loading yarns into a textile machine

ABSTRACT

The invention relates to an apparatus for presenting threads for loop-forming tools, arranged in at least one row, of a textile machine having a thread guide apparatus having at least one rotary element (4, 5, 20, 21, 30, 31, 40, 41) having at least one thread guide (20a, 20b, 21a, 21b 30a, 30b, 40a, 40b), said thread guide apparatus being configured to lay a thread back and forth in two directions (HI, HR) in each case in front of a row of the tools in an entire stroke range (BG). The thread guide apparatus has at least two rotary elements (4, 5) arranged as a pair, wherein the rotary elements (4, 5, 20, 21, 30, 31, 40, 41) of a pair are arranged eccentrically with respect to one another and one above another in the axial direction, and wherein the rotary elements (4, 5) of a pair are drivable in opposite directions of rotation (R1, R2). Each rotary element (4, 5, 20, 21, 30, 31, 40, 41) has at least one thread guide (4a, 4b, 4c, 5a, 4b, 4c, 20a, 20b, 21a, 21b, 30a, 30b, 40a, 40b), configured as a driver element, for laying the thread in one of the directions (HI, HR).

The invention relates to a method and apparatus for loading yarns into at least one row of stitch-forming tools of a textile machine and to a corresponding textile machine.

A textile machine for warp knitting, in particular a Raschel warp-knitting machine, is described for example in DE 1 268 305. A yarn that used as a weft yarn is displaced by a yarn guide of a long weft device that can be moved between two reversal points by an actuating cylinder approximately parallel to the row of knitting needles at the rear side thereof during a stitch-forming operation. At the moment in which the needles are in the knock-over position transverse to the row of needles, the weft yarn is brought to the front side of the row of knitting needles under the effect of suction nozzles.

Since the yarn guide must be accelerated and decelerated between the reversal points, the speed at which the yarn guide can be moved by the actuating cylinder is limited.

DE 17 60 860 [U.S. Pat. No. 3,643,471] discloses an apparatus for loading weft yarns into warp-knitting machines, in particular for Raschel warp-knitting machines, in which a yarn guide moves around in an annular path. A rotor in the form of a rod is provided at the end of the yarn guide. The rod is rotatable in one direction about an axis perpendicular to its longitudinal direction of extension. The weft yarn is guided from the bobbin through the axis of the rod to the yarn guide. Retaining elements are provided near the edges of the material web about which the weft yarns can be looped by the yarn guide. The drive for the retaining elements is coordinated with the rotational movement of the rod such that the weft yarns do not cross between the retaining elements. The retaining elements also serve as guide members for laying the weft yarns against the warp yarns.

A warp-knitting machine, in particular a Raschel warp-knitting machine, with an apparatus for loading a weft yarn is known from DE 1 920 477. The weft yarn is gripped outside the needle zone by retaining members that are near the edges of the material web and laid against the warp yarns by guide members. For the purpose of loading the weft yarn, a plurality of yarn guides are provided that are guided in a closed path and that each has a respective bobbin holder.

Storage elements for receiving a plurality of lengths of weft yarn corresponding to the product width are between the yarn guides and the knitting needles.

An apparatus for loading weft yarns to warp-knitting machines is described in DE 20 35 007. It comprises a yarn guide consisting of a tube that is guided by a circulating belt over reversal points near the edges of the material web. Storage devices are provided that receive the individual lengths of weft yarn and are moved toward the knitting tools.

A warp-knitting machine, in particular Raschel warp-knitting machine, for manufacturing warp-knit goods with long weft yarns with a device for continuous supply of a plurality of weft yarns is described in DE 24 01 050. A carriage places the weft yarns between a pair of conveyor belts that feed the weft yarns to the knitting tools.

It is the object of the invention to develop a method and apparatus for loading yarns into stitch-forming tools of a textile machine as well as a corresponding textile machine with which the yarns are loaded into the tools at high speed. In particular, the speed of reciprocal laying is to be increased. This object is attained by the characterizing features of the independent claims.

An apparatus according to the invention for loading yarns into at least one row of stitch-forming tools of a textile machine comprises a yarn loader having at least one rotor with at least one yarn guide. The yarn loader lays a weft yarn back and forth in two directions in the region in front of itself over tools of the textile machine over a stroke range.

The yarn loader has at least two rotors provided as a pair, the rotors of each pair being axially one above the other and rotate in opposite directions of rotation. Each rotor comprises at least one yarn guide formed as a driver element for laying the weft yarn in one of the directions.

In one embodiment, the driver elements are guide arms. The formation of the yarn guides as guide arms makes it possible to effortlessly guide yarns through tubes or eyelets.

So-called traversing devices with rotors that are driven in opposite directions are known for winding yarns into cross-wound packages. DE 83 02 278 describes a winding machine for winding yarns onto bobbin tubes with a traversing device through which the yarn is laid back and forth substantially transverse to the direction of travel over a traverse stroke that corresponds substantially to the bobbin length. The traversing device comprises two rotors that are supported eccentrically relative to one another and driven so as to rotate in opposite directions. Each of the rotors has at least two driver arms, the driver arms of the two rotors rotating on two closely spaced planes of rotation that are penetrated by the yarn course.

In contrast to the winding of rotating cross-wound packages, the yarn is fed, i.e. made available, to the tools with the device according to the invention and taken up during stitch formation.

A yarn loader with at least two rotating yarn guides, one for each direction of the reciprocating motion in front of the stitch-forming tools, makes a much higher speed possible in the laying the yarn than with known yarn loaders. This simplifies the presentation of the yarn and thus the entire mechanical complexity of the textile machine.

In warp-knitting machines, speeds of 1500 meters per minute, for example, can be achieved with the yarn loader laying a weft yarn back and forth. For certain warp-knitting machines, for example for many Raschel warp-knitting machines, this speed is sufficient to enable the weft yarn to be fed in without an additional storage device.

The use of this fast yarn loader offers new uses, such as in the manufacture of nets, reinforcement textiles, geotextiles, or lace.

In one embodiment, the yarn loader lays in the yarn over a stroke range per pair of rotors of from 0.05 cm to 100 cm, in particular from 0.5 cm to 50 cm.

In one embodiment, the device comprises a feeding device that supplies the yarn that is laid in one direction to the tools. For example, the feeding device is embodied as a gripper that extends along the tools.

In one embodiment, the device has a holding device with two retaining elements that are near reversal points of the yarn spaced apart by the stroke range. Each retaining element receives the yarn that is laid by the yarn loader in a respective one of the directions.

In one example, the retaining device supplies the retained yarn to the tools. In an alternative example, a feeding device is provided in addition to the retaining device.

A yarn loader with two rotating yarn guides, each for one direction of the reciprocating motion, makes it possible to set a phase shift between the two yarn guides.

The angle between the starting position of the first yarn guide of the upper rotor of a pair that lays the yarn in one direction and the starting position of the second yarn guide of the lower rotary member taking the yarn and laying the yarn back in the other direction is referred to as constant phase shift if the two rotating elements rotate in opposite directions at the same rotational speed. A changing phase shift is produced by different rotational speeds of the rotating elements of a rotor pair.

In one example of a pair with two rotors, each rotor has a yarn guide formed as a guide arm. Each yarn guide is lays the yarn in one direction over a half turn, i.e. a rotation by 180°, over the stroke range. In the case of a 0° phase shift of the two yarn guides of the rotating elements driven in opposite directions of rotation, that is, at the same starting position, the yarn is alternately laid back and forth by one and the other yarn guide.

In an alternative of this example, each yarn guide lays the yarn in one direction at one-quarter of a turn, i.e. a rotation by 90°, over the stroke range. In the case of a 180° phase shift of the two yarn guides of the rotating elements driven in opposite directions of rotation, the yarn is laid by a yarn guide in one direction, held at a yarn reversal point, laid by the other yarn guide in the other direction, and again held at the yarn reversal point. The yarn is held in a feeding device, for example, or at the yarn reversal points, by the retaining device.

In one embodiment, the rotors each have at least two yarn guides. During one turn of the corresponding rotor, the yarn can be laid twice in the corresponding direction if the rotor has two yarn guides, for example.

In one embodiment, the yarn guides of a rotor, which are guide arms, for example, are provided so as to be distributed angularly uniformly.

In one alternative, they are angularly unevenly distributed.

In one embodiment, the yarn loader comprises a number of pairs, each with two rotors. The pairs are side by side. The yarn loader lays the yarn over a stroke range by each pair, this stroke range corresponding to a full machine width divided by the number of pairs. In this case, the yarn to be laid in one direction is transferred from one pair of rotors to the next pair. The overall size of the rotors increases with increasing stroke range and reaches the limits of the space that is available in the textile machine. The arrangement of multiple pairs next to one another enables the overall size to be reduced or the stroke width to be increased. If multiple pairs of rotors are provided, a total stroke range up to about 600 cm is possible.

A textile machine according to the invention with at least one row of stitch-forming tools has one of each of the loaders described above for each row of tools.

Textile machines with at least one row of stitch-forming tools include warp-knitting machines, namely automatic warp-knitting machines, Raschel warp-knitting machines and crochet galloon machines, as well as stitch-bonding machines and flat-knitting machines. A yarn that is to be fed to tools of a warp-knitting machine or of a stitch-bonding machine or knitting tools or of a flat-knitting machine that are designated as knitting tools is a warp yarn or as a weft yarn.

When the yarn for the stitch-forming tools is presented, the yarn that is laid in at least one direction is placed in front of, behind, or over the tools.

The features and advantages of the method claims are substantially the same as those of the corresponding device claims.

The invention will be explained in further detail on the basis of examples that are illustrated schematically in the drawing. The illustrated examples relate to textile machines according to the invention that are warp-knitting machines with an apparatus according to the invention for laying yarns for a textile machine, specifically for loading weft yarns for the warp-knitting machine. In the drawing:

FIG. 1 is a schematic view of the principle of a warp-knit fabric with a weft yarn;

FIG. 2a is a schematic perspective view of a pair of rotors of a first device according to the invention for loading yarns in a first position;

FIG. 2b is a schematic view corresponding to FIG. 2a in a second position;

FIG. 3 is a schematic view of a textile machine according to the invention embodied as a warp-knitting machine with the apparatus according to the invention of the first example;

FIG. 4 is a view of the principle of another warp-knit fabric with a weft yarn; and

FIG. 5 is a schematic view of three pairs of rotors of a second device according to the invention for loading yarns.

FIRST EXAMPLE

In the first example, the textile machine is a warp-knitting machine with an apparatus for loading yarns as weft yarns in front of a row of knitting tools.

FIG. 1 is a schematic illustration of a section of a narrow strip of a warp-knit fabric that can be produced by the warp-knitting machine. The warp-knitting machine is embodied, for example, as an RL Raschel warp-knitting machine with one row of knitting tools, with “RL” meaning right-left stitching. In the illustrated example, the warp-knit fabric is composed of five stitch-forming warp yarns 1 and one weft yarn 2. FIG. 1 shows a cutaway row of stitches and four complete rows of stitches with three weft reversal points 3.

The apparatus for loading the weft yarn for the knitting tools has a yarn loader. FIGS. 2a and 2b show the principle of the yarn loader in a perspective view. It lays the weft yarn 2 back and forth in two directions HI, HR in the region in front of the knitting tools of the warp-knitting machine that extend over a full machine width B indicated in FIG. 2 b.

The yarn loader has two rotors 4 and 5 provided as a pair. The rotors 4 and 5 are in front of a row of knitting tools, with knock-over bits 6 and five latch needles 7 of the knitting tools of the warp-knitting machine being visible in FIGS. 2a, 2b . The rotors 4 and 5 of the pair are one above the other in the direction of their common axis D shown in FIG. 3. The rotors 4 and 5 of the pair can be driven in opposite directions of rotation R1, R2. In the example shown in FIGS. 2a, 2b , the rotor 4 is above the rotor 5. In this example, the axis of rotation of the two rotors 4 and 5 is parallel to the direction of movement RZ of the latch needles 7 and thus perpendicular to the row of knitting tools.

Each rotor 4 and 5 has three yarn guides 4 a, 4 b, 4 c, 5 a, 5 b, 5 c that are driver elements for laying the weft yarn 2 in one of the directions HI, HR.

In a first position shown in FIG. 2a , the warp yarns 1 coming from above in FIGS. 2a and 2b are guided around the latch needles 7 to form a next stitch above the latch 7 a of the latch needle 7. Each of the warp yarns 1 forms a stitch beneath the latch 7 a of the latch needle 7 into which a knit portion 2G of the weft yarn 2 running from left to right is already incorporated in FIG. 2a . In FIG. 2a , the weft yarn 2 is laid by the yarn guide 4 a of the rotary member 4 in the direction HI in front of two latch needles 7 starting from the weft reversal point 3.

FIG. 2b shows the transfer of the weft yarn 2 from the yarn guide 4 a of the upper rotor 4 to the yarn guide 5 a of the lower rotor 5. The latch needles are in a knock-over position.

FIG. 3 shows a schematic and not-to-scale illustration of the warp-knitting machine with the apparatus for loading the weft yarn 2 in front of the knitting tools, particularly as a schematic vertical cross section. The yarn loader with the rotors 4 and 5 are in front of the knitting tools 7 of the knitting machine. The position of the rotors 4 and 5 corresponds to that of FIG. 2 a.

One of the latch needles 7, one of the knock-over bits 6, one of the guide needles 8, and one of the warp yarns 1 of the knitting tools are shown. The warp yarns 1 are guided through the guide needles 8 to the latch needles 7. The weft yarn 2 is guided from a bobbin 9 to the yarn guide 4 a of the rotor 4 that lays it in front of the latch needle 7 beneath the latches 7 a.

The rotors 4 and 5 of a pair are provided such that the rotating yarn guides 4 a, 4 b, 4 c, 5 a, 5 b, 5 c cross the yarn path of the weft yarn 2 from the bobbin 9 to the knitting tools.

The warp-knitting machine is indicated by a rear side wall 10 and a base 11. The warp-knitting machine has a pair of rollers 12 and a take-up roll 13 for winding up the warp-knit fabric KG produced in the take-off direction P downstream of the knitting tools (left side in FIG. 3).

During operation, the weft yarn 1 is laid back and forth by the yarn loader in the region in front of the knitting tools of the warp-knitting machine in two directions HI, HR that extend over the complete stroke width B.

The rotors 4 and 5 of the yarn loader that are provided as a pair are axially one above the other and driven in opposite directions of rotation R1, R2. The weft yarn 2 is respectively laid by the yarn guides 4 a, 4 b, 4 c, 5 a, 5 b, 5 c that are guide arms in one of the directions HI, HR. That is, in the yarn path of the weft yarn 2 from the bobbin 9 to the knitting tools, the weft yarn 2 is grasped, laid back and forth, and thus presented to the knitting tools by the rotating yarn guides 4 a, 4 b, 4 c, 5 a, 5 b, 5 c of the rotors 4 and 5 of a pair.

The weft yarn 2 is laid by the yarn guides 4 a, 4 b, 4 c of the rotor 4 in the direction HI (from right to left in FIGS. 2a, 2b ) and by the yarn guides 5 a, 5 b, 5 c of the rotary member 5 in the direction HR (from left to right in FIGS. 2a, 2b ). The weft yarn 2 is guided alternately by the yarn guides 4 a, 4 b, 4 c of the rotor 4 and the yarn guides 5 a, 5 b, 5 c of the rotor 5. As is shown in FIG. 2b , the weft yarn 2 is taken over by the yarn guide 5 b from the yarn guide 4 a for this purpose, for example.

In an alternative example, the axis of rotation of the two rotors extends at an acute angle relative to the direction of movement RZ of the latch needles 7.

In an alternative example, the two rotors of a pair are provided eccentrically parallel to the row of knitting tools.

In an alternative example, the warp-knitting machine is embodied as an RR Raschel warp-knitting machine with two rows of knitting tools. The warp-knitting machine has an apparatus for loading a weft yarn for each of the two rows.

Second Example

The second example corresponds to the first example except for the features described below.

FIG. 4 shows a schematic illustration of a section of a narrow strip of a warp-knit fabric KG. In the illustrated example, the warp-knit fabric KG is composed of nine stitch-forming warp yarns 1 and one weft yarn 2. FIG. 1 shows a cutaway row of stitches and nine complete rows of stitches. In the upper five rows of stitches with five weft reversal points 3, the weft yarn 2 is guided around all of the stitches of a row. In the lower four rows of stitches, the weft yarn 2 is guided only by a portion of the stitches, namely by four stitches, with two inner weft reversal points 3 i being formed in addition to an additional, outer weft reversal point 3.

FIG. 5 shows the principle of a yarn loader of the device of the second example. The yarn loader comprises a number N of three pairs, each with two rotors 20, 21, 30, 31, 40, 41, each of which has two yarn guides 20 a, 20 b, 21 a, 21 b, 30 a, 30 b, 31 a, 31 b, 40 a, that are guide arms 40 b, 41 a, 41 b. The three pairs are side by side along an entire stroke range BG. Each pair is lays the weft over a partial stroke range BT. The stroke range BT corresponds to the full machine width BG divided by the number N of the pairs, i.e. divided by 3.

The stroke range BT of a pair of rotary members 20, 21, 30, 31, 40, 41 is 3 cm in this example. The full machine width BG is 9 cm, for example.

During operation, the weft yarn 2 is laid by one pair of three juxtaposed pairs, each with two rotors 20, 21, 30, 31, 40, 41, over a stroke range BT, which corresponds to the full machine width BG divided by the number N of pairs. This is shown for the top five rows of stitches of the warp-knitted fabric KG shown in FIG. 4.

In the lower four rows of stitches of the warp-knit fabric KG shown in FIG. 4, the weft yarn 2 is laid by the right pair of rotary members 20, 21 over the right three stitches and by the middle pair of rotary members 30, 31 over one stitch.

In an alternative, the stroke range of a pair of rotary members is from 0.5 cm to 50 cm.

In an alternative of a warp-knit fabric, multiple layers of weft yarns are provided.

In that case, multiple weft yarns are moved back and forth simultaneously by a plurality of pairs of rotors of the yarn loader and fed one above the other to the knitting tools.

Such warp-knit fabrics can be used in lightweight construction, for example for composite structures in wind turbines or in automobiles.

List of Reference Symbols  1 warp yarn  2 weft yarn  2G knit portion  2S bobbin portion  3 weft reversal point  4 rotor 4a-4c yarn guide  5 rotor 5a-5c yarn guide  6 knock-over bit  7 latch needle  7a latch  8 guide needle  9 bobbin 10 side wall 11 foundation 12 pair of rollers 13 take-up roll 20, 21 rotors 20a, 20b, 21a, 21b yarn guide 30, 31 rotors 30a, 30b, 31a, 31b yarn guide 40, 41 rotors 40a, 40b, 41a, 41b yarn guide B stroke range RZ direction R1 direction of rotation R2 direction of rotation HI direction HR direction P take-off direction KG warp-knit fabric BG full machine width BT stroke range of one pair 

1. An apparatus for loading yarns into at least one row of stitch-forming tools of a textile machine, comprising a pair of yarn loader each having a pair of rotor rotating in opposite directions about a common axis and one axially above the other, at least one yarn guide, on each of the rotors operable to lay a yarn back and forth in two directions along a full machine width in front of the row of tools, being formed as a driver element for laying the yarn in a respective one of the directions.
 2. The device according to claim 1, further comprising: a feeding device that supplies the yarn that is laid in a respective one of the directions to the tools.
 3. The device according to claim 1, further comprising a retaining device with two retaining elements that are near reversal points of the yarn spaced apart by the full machine width, the retaining devices each receiving the yarn laid by the yarn loader in a respective one of the directions and supplying it to the tools.
 4. The device according to claim 1 wherein the rotors each have at least two yarn guides.
 5. The device according to claim 1, in that wherein the yarn loader comprises a number of pairs of rotors, the pairs being side by side with each pair laying the yarn over a respective stroke range corresponding to the full machine width divided by the number of pairs.
 6. A textile machine comprising at least one row of stitch-forming tools and having an apparatus according to claim 1 for each row of tools.
 7. A method for loading yarns into at least one row of stitch-forming tools of a textile machine having a yarn loader having at least one pair of rotors rotatable about a common axis one above the other and each having at least one yarn guide the method comprising the steps of: rotating the rotors in opposite directions of rotation; and engaging the yarn guides as driver elements with the yarn being to lay the yarn in a respective one of the directions by each rotor.
 8. The method according to claim 7, further comprising the step of: feeding the yarn laid in one direction by a feeding device to the tools.
 9. The method according to claim 7, further comprising the step of: laying the yarn laid in the directions by two respective retaining devices that are near reversal points of the yarn spaced apart by the full machine width and thereby supplying the yarn to the tools.
 10. The method according to any one of claim 7 wherein the yarn is laid by one respective pair of a number of pairs, each with two rotors of the yarn loader, over a stroke range that corresponds to the full machine width divided by the number of pairs. 